Screen flickers every 17 seconds - Desktop Window Manager (dwm.exe)

This problem has affected the last few builds of Windows 10 Pro x64 Insider Preview, including the latest 1903 version build 18356.1.

Every 17 seconds the monitors flicker. I've found that the times that the flash occurs coincides exactly with an entry in the Windows Logs > Application event log:

Event ID: 9027
Source: Desktop Window Manager
Details: The Desktop Window Manager has registered the session port

Using SysInternals' 'Process Explorer' I can see 4 dwm.exe processes running. 3 of these processes started yesterday when the machine was rebooted. Every 17 seconds (i.e., when the screens flicker) the 4th dwm.exe process is killed and a new one is created.

At the same time that the 4th dwm.exe processes is restarted I also see a few other processes killed and restarted:

• csrss.exe - 5 processes running, latest process to start is killed and restarted every 17 seconds
• fontdrvhost.exe - 5 processes running, latest is killed and restarted every 17 seconds
• logonui.exe - 1 process running, killed and restarted every 17 seconds
• NVDisplay.Container.exe - 5 processes running, latest process to start is killed and restarted every 17 seconds
• winlogon.exe - 4 processes running, latest process to start is killed and restarted every 17 seconds
• WUDFHost.exe - 6 processes running, latest process to start is killed and restarted every 17 seconds

The screen flash is becoming quite annoying! Can it be stopped?

Many thanks!

/Neil

It took several hours for me to track down this issue. I'm not sure EXACTLY why it's doing this - but here's my symptoms and solution...

After updating to Windows 10 1903 - my desktop kept flashing almost every 17 seconds -- pretty regular interval.
Tried upgrading GPU drivers, DDU, etc. Didn't solve it.
Shut off startup / services and after a lot of pain-in-the-butt work, narrowed it down to Remote Desktop Services.
I see the 9027 entry as noted by the original post.
Drilling into Applications and Service Logs -> Microsoft -> Windows -> TerminalServices-RemoteConnectionManager
There I noticed some jerk trying to brute-force my RDP. (Hate the A-holes of the world... sigh)

So my screen was still flashing (unless I disable termservices / Remote Desktop). Tested my theory by going to the router and blocking 3389. Poof - flashing stopped. Re-enable 3389 -- flashing starts.

So my fix is to map another port. Hope this helps others out there.

This problem is a byproduct of the change from XDDM to WDDM driver model.

Add this registry key to force XDDM and the flickering should go away without disabling RDP.

HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services\fEnableWddmDriver DWORD 0

njellis said:

It took several hours for me to track down this issue. I'm not sure EXACTLY why it's doing this - but here's my symptoms and solution...

After updating to Windows 10 1903 - my desktop kept flashing almost every 17 seconds -- pretty regular interval.
Tried upgrading GPU drivers, DDU, etc. Didn't solve it.
Shut off startup / services and after a lot of pain-in-the-butt work, narrowed it down to Remote Desktop Services.
I see the 9027 entry as noted by the original post.
Drilling into Applications and Service Logs -> Microsoft -> Windows -> TerminalServices-RemoteConnectionManager
There I noticed some jerk trying to brute-force my RDP. (Hate the A-holes of the world... sigh)

So my screen was still flashing (unless I disable termservices / Remote Desktop). Tested my theory by going to the router and blocking 3389. Poof - flashing stopped. Re-enable 3389 -- flashing starts.

So my fix is to map another port. Hope this helps others out there.

I looked around for a while to try to figure this out as well. We were already using a non-standard port for RDP, so once I found that this was our issue as well I was surprised. We have more than one user using RDP so it would have been a pain to change the port.

I could see from the RemoteConnectionManager event log (referenced above) that there were two (and only two) separate IP addresses (one in California and one in Russia) trying to gain access through RDP. Instead of changing the TCP port I created an entry in the Windows firewall to block incoming connections from those two IP addresses. If I see it happening again we will consider either a more advanced router that can block the connections or setting up a VPN.

Thank you for posting your experience! It saved me lots of time!